Boxcar Averaging Scanning Nonlinear Dielectric Microscopy.

Scanning nonlinear dielectric microscopy (SNDM) is a near-field microwave-based scanning probe microscopy method with a wide variety of applications, especially in the fields of dielectrics and semiconductors. This microscopy method has often been combined with contact-mode atomic force microscopy (AFM) for simultaneous topography imaging and contact force regulation. The combination SNDM with intermittent contact AFM is also beneficial for imaging a sample prone to damage and using a sharp microscopy tip for improving spatial resolution.

Scanning nonlinear dielectric potentiometry.

Measuring spontaneous polarization and permanent dipoles on surfaces and interfaces on the nanoscale is difficult because the induced electrostatic fields and potentials are often influenced by other phenomena such as the existence of monopole fixed charges, screening charges, and contact potential differences. A method based on tip-sample capacitance detection and bias feedback is proposed which is only sensitive to polarization- or dipole-induced potentials, unlike Kelvin probe force microscopy. The feasibility of this method was demonstrated by simultaneously measuring topography and polarization-induced potentials on a reconstructed Si(111)-(7 × 7) surface with atomic resolution.

Persistence of chaos in a time-delayed-feedback controlled Duffing system.

This paper concerns global phase structures of a time-delayed-feedback controlled two-well Duffing system. The remains of a global stretch and fold structure along an unstable manifold, which develops from an unstable fixed point in function space, reveals that the global chaotic dynamics is inherited from the original system by the controlled system. The remains of the original chaotic dynamics causes a highly complicated domain of attraction for target orbits and a long chaotic transient before convergence.

Domain of attraction for stabilized orbits in time delayed feedback controlled Duffing systems.

Time delayed feedback control is well known as a practical method for stabilizing unstable periodic orbits embedded in chaotic attractors. However, this control method still has an open problem of estimating domain of attraction for target unstable periodic orbits. In this paper, we numerically discuss the domain of attraction in Duffing systems under the control method.